<!DOCTYPE html>
<meta charset="utf-8">
<style>
html, body {
    margin: 0;
    padding: 0;
}

.green {
    position: absolute;
    border-radius: 50px;
    background: green;
    padding: 50px;
    width: 100px;
    height: 100px;
}

.red {
    position: absolute;
    top: 50px;
    left: 50px;
    width: 100px;
    height: 100px;
    background: red;
    border-radius: 50%;
}
</style>
<div class="green"></div><div class="red"></div>

